The assignee of the present invention, ebm-papst St. Georgen GmbH & Co. KG (hereinafter simply “PAPST”) manufactures small motors which serve, for example, for cooling of the processors in computers, for device cooling of other small devices, etc. These motors have small dimensions. For example:    fans of the PAPST Series 250 have dimension 8×25×25 mm;    fans of the PAPST Series 400F have dimensions 10×40×40 mm;    fans of the PAPST Series 400 have dimensions 20×40×40 mm;    fans of the PAPST Series 600 have dimensions 25.4×60×60 mm. The power consumption of such fans falls in the range from 0.4 to 0.6 watts for the Series 250, 0.7 to 0.9 watts for the Series 400F, and 0.9 to 1.6 watts for the Series 400 and 600.
External rotor motors in the form of small or miniature motors are often used to drive fans, e.g. those in computers for cooling of the processors. The components of such motors are so small that they look like toys or parts of watches. This is necessary, in order that such motors can, despite their smallness, be assembled simply, with high precision, and economically, preferably by means of an automated assembly process.